package thread;

public class SyncDemo4 {
    public static void main(String[] args) {
        Boo boo = new Boo();
        Thread t1 = new Thread(){
            public void run() {
                boo.methodA();
            }
        };
        Thread t2 = new Thread(){
            public void run() {
                boo.methodB();
            }
        };
        t1.start();
        t2.start();

    }
}
class Boo {
    public void methodA(){
        synchronized(this) {
            try {
                System.out.println("正在执行A方法");
                Thread.sleep(5000);
                System.out.println("执行A方法完毕");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
    public void methodB(){
        synchronized("") {
            try {
                System.out.println("正在执行B方法");
                Thread.sleep(5000);
                System.out.println("执行B方法完毕");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}